Coder apparatus for resonant power conversion and method
View Patent ↗An Nth-order shaping coder with multi-level quantization and dithered quantizer. The coder is inherently stable and produces a purely white quantization error spectrum. In one exemplary embodiment, the coder is first order, and an improved dither scheme is employed including applying a M-times (e.g., M=2) sample-and-hold to the dither sequence, effectively holding a constant dither for multiple clock cycles. This advantageously results in a reduction of instances where the quantizer jumps over two quantization intervals in one clock cycle without first passing through zero for one clock cycle. Methods for implementing the shaping coder are also disclosed.
1. A digitally actuated resonant power (DARP) converter comprising:
a dithered first order multi-level quantized noise-shaping encoder for receiving digital data at a clock rate Fc/L1, where L1 equals 2 or more and Fc is a carrier frequency, and encoding the digital data;
a power supply, having a frequency at or substantially near DC;
a resonator having a resonant frequency at or substantially near the carrier frequency Fc;
a load impedance coupled to the resonator for receiving energy stored in the resonator; and
a charging switch, the charging switch coupled to the first-order noise-shaping encoder, the power supply, the resonator, and a clock having a clock rate (L2)(Fc), where L2 equals 2 or more, the charging switch adapted to:
(i) receive encoded data from said first-order noise-shaping encoder;
(ii) sample the voltage or current of said power supply; and
(iii) deliver said power supply voltage or current samples to said resonator.
2. The converter in accordance with claim 1 , further comprising:
a dither generator generating dither samples at a dither sample rate lower than a coder sample rate of the coder, wherein the dither samples are used for dithering during the quantization; and
wherein the coder is adapted to process an input signal containing the received digital data.
3. The coder in accordance with claim 2 wherein the dither sample rate is M times less than the coder sample rate, where M is greater than one.
4. The coder in accordance with claim 3 wherein M equals a power of 2.
5. The coder in accordance with claim 2 wherein the dither generator comprises a PN sequence generator.
6. The coder in accordance with claim 5 wherein the PN sequence generator operates at a clock rate equal to the coder sample rate divided by M, where M is greater than one.
7. The coder in accordance with claim 5 further comprising a sample/hold decimation apparatus that decimates the dither samples by M, where M is greater than one.
8. A method for implementing noise shaping coding for use in a digitally actuated resonant power (DARP) converter, comprising:
providing an input signal to a dithered first order multi-level quantized noise-shaping coder receiving digital data at a clock rate Fc/L1, where L1 equals 2 or more and Fc is a carrier frequency, and encoding the digital data;
providing power a power supply having a frequency at or substantially near DC from a power supply;
receiving energy stored in a resonator having a resonant frequency at or substantially near the carrier frequency Fc at a load impedance coupled to the resonator;
employing a charging switch, the charging switch coupled to the first-order noise-shaping coder, the power supply, the resonator, and a clock having a clock rate (L2)(Fc), where L2 equals 2 or more, to:
(i) receive encoded data from said first-order noise-shaping encoder;
(ii) sample the voltage or current of said power supply; and
(iii) deliver said power supply voltage or current samples to said resonator;
generating dither samples at a dither sample rate less than the coder sample rate;
dithering the input signal using the dither samples; and
applying multi-level quantization to the dithered input signal.
9. The method in accordance with claim 8 further comprising:
generating the dither samples at the dither sample rate that is M times less than the coder sample rate, where M is greater than one.
10. The method in accordance with claim 9 wherein M equals a power of 2.
11. The method in accordance with claim 8 further comprising:
generating the dither samples with a PN sequence generator.
12. The method in accordance with claim 11 further comprising:
operating the PN sequence generator at a clock rate equal to the coder sample rate divided by M, where M is greater than one.
13. The method in accordance with claim 11 further comprising:
sampling and holding the PN sequence dither samples by a factor M, where M is greater than one.